1. Field of the Invention
The device and method of this invention relate to a jig assembly and method for constructing suspended strut racks and more particularly relate to a jig assembly having multiple parts that are adjustable for receipt of channel members, nuts and associated hardware for their pre-assembly before installation in a building for supporting utility structures in such building.
2. History of the Prior Art
Metal framing systems used in building construction especially in large buildings are well known in the prior art. Such systems utilize an array of support structures for suspending conduits and other electrical components from the ceiling. A typical support structure consists frequently of a pair of threaded rods which are attached vertically to the ceiling and attached to these threaded rods are a plurality of horizontal channel members at different levels, forming what are referred to as trapeze-type support systems. These systems are installed by contractors who must build each support structure by hand by first taking each channel member and in multiple parallel locations on the threaded rods spacing them apart from one another by first manipulating in order a nut, a lock washer and a square washer above each channel member and immediately below the channel member in descending order a square washer, a lock washer and a nut. These nuts must be threaded by hand onto each threaded rod until the channel members are in their desired position on each threaded rod. The channel members are positioned at various heights on the threaded rods in a series so as to be able to hold multiple levels of conduits thereon. Once the metal framing system has been constructed by the manual rotating of each nut, followed by a lock washer and a square washer to surround and to hold each channel member in its desired location on the threaded rods, the threaded rods are then threaded into attachment members on the ceiling of the building and hang down therefrom. Conduits and other structures can then rest on the channel members.
It is a highly labor-intensive process for the nuts to be threaded from the end of each threaded rod up to their desired positions, and then the lock and square washers and channel members have to be pushed thereon with the then lower nuts threaded thereon by hand. Some threaded rods can be up to 10 feet in length so that a great deal of work is involved in threading each individual nut thereon. This process has to be performed multiple times for the desired number of channel members which are attached to the threaded rods. It is thus very costly and time-consuming to use the current method of installing channel members during building construction.